Investigate Clinical Evidences For Chlamydia Pneumoniae As A Causative Factor Of Ankylosing Spondylitis And Study Immuno-pathological Characteristics Of Synovial Tissue

【Objective】To investigate the evidence of chlamydia pneumoniae infection as a causative factor for ankylosing spondylitis, and immunohistochemistical detection of hip synovial tissuses in AS patients.【Methods】Polymerase chain reaction(PCR) was used to amplify chlamydia pneumoniae DNA and immunofluorescence assay(IF) used to detect chlamydia LPS antigen in peripheral blood cells from 33 proven AS patients and 22 healthy blood donors. Immunohistochemistical technique was applied to examine chlamydia LPS antigen in synovial tissue from another 9 AS patients who received total hip replacement and 13 patients with comminuted femoral fractures.immuno-pathological change of the synovium was also examined in 5 AS patients.【Results】1 The PCR positive rates of chlamydia pneumoniae DNA in AS group is 33.3%, significantly higher than that in control group(9.1%),χ2 = 4.298, P =0.038.2 Chlamydia LPS antigen was found in PMBCs from 63.3% AS patients while only 31.8% in control group,χ2 =6.431,P=0.011.3 Positive results of PCR correlated with the level of acute phase protein in AS patients: CRP, Z= -2.774, P=0.004;ESR,Z=-2.829, P=0.004.4 In synovial tissues, Chlamydial LPS-containing inflammatory cells was observed in 77.8% AS patients, compared with 37.7% in patients with comminuted femoral fractures, P=0.08.5 Immunohistochemical analysis revealed lymphocytes gathered in 4 cases,and lymphoid follicles was formed in one case, charactered by appearance of abundant IgG4 positive plasma cells infiltration. 【Conclusion】1 peripheral blood Cp infection occurred more frequently in AS patients and may associated with the pathogensisis of Ankylosing spondylitis.2 Chlamydia LPS was detected in AS patients'synovial tissuses suggesting that the deposition of chlamydia LPS in synovial tissuses may result the hip involvement.3 IgG4-releted pathogenic machanism may be involved in the process of AS development.